- 标题
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Double sites occupancy of Mn4+ in Cs2NaAlF6 with enhanced photoluminescence for white light-emitting diodes
摘要： In this work, we present a novel single-phase red phosphor of Cs2NaAlF6:Mn4t with two Al3t lattice sites, which shows two groups of vibrational phonon sidebands and ultra-intense zero phonon line (ZPL) under blue light illumination. The evidences have shown that the interesting spectral features originate from the non-equivalent occupation of Mn4t for both Al3t sites, which induces the neighboring cation vacancies surrounding Mn4t and highly distorted [MnF6] octahedral in the Cs2NaAlF6 host. The luminescent behavior of double sites occupied by Mn4t can absorb researchers’ interest on novel red-emitting phosphors. Pro?ting from the photoluminescence (PL) features, superior color rendering index of Ra ? 90.3, R9 ? 81, and low correlated color temperature of Tc ? 3967 K are achieved from white light-emitting diode (LED) by using yellow Y3Al5O12:Ce3t (YAG) and red Cs2NaAlF6:Mn4t phosphors as blue light converters. These results suggest that Cs2NaAlF6:Mn4t phosphor has a stupendous potential for LED lighting.
关键词： Red phosphor,Cs2NaAlF6:Mn4t,Luminescence properties,LED,Double sites occupancy
更新于2025-09-23 15:21:01
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Synthesis and photoluminescence properties of Sm3+ and Dy3+ ions activated double perovskite Sr2MgTeO6 phosphors
摘要： A series of double perovskite Sr2MgTeO6:Sm3+/Dy3+ phosphors for solid-state lighting application were successfully synthesized by the solid-state reaction process. The phase structure, photoluminescence, thermal quenching, and decay behavior of the prepared phosphors were investigated. The photoluminescence of Sr2MgTeO6:Sm3+ exhibits red emission (640 nm) due to the transition from the 4G5/2 → 6H7/2 under 404?nm excitation. Sr2MgTeO6:Dy3+ exhibits two emission bands under 390?nm excitation. They are due to 4F9/2 → 6H15/2 (blue) and 4F9/2 → 6H13/2 (yellow) transitions of Dy3+, respectively. Sr2MgTeO6:0.10Sm3+ phosphor shows excellent thermal stability. Therefore, Sr2MgTeO6:Sm3+/Dy3+ phosphors are a promising candidate for UV chip-based WLED and solid-state lighting.
关键词： Phosphor,Sr2MgTeO6:Sm3+,Luminescence,Sr2MgTeO6:Dy3+,Tellurate
更新于2025-09-23 15:21:01
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Multicolor Persistent Luminescence Realized by Persistent Color Conversion
摘要： Spectral tuning is important for the development of persistent phosphors. Here we introduce a color conversion concept to obtain abundant persistent luminescence spectra in addition to existing methods of exploring new matrix and/or dopants. In this study, CaAl2O4:Eu,Nd was chosen as a blue persistent donor phosphor, while Lu3Al5O12:Ce and other four commercial phosphors were explored as conversion phosphors to obtain colorful persistent luminescence spectra. Both the persistent donor phosphor and conversion phosphors were embedded into resin, forming ternary composite chips to ensure efficient energy transfer. Continuous color tuning were realized by simply changing the mass ratio of the persistent donor phosphor vs. conversion phosphor. Our work will be significant in indicating other persistent/conversion composite materials or nanostructures with abundant spectral properties.
关键词： composite,Persistent luminescence,afterglow,persistent phosphor,spectral tuning
更新于2025-09-23 15:21:01
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Tunable bluea??greena??emitting Na4CaSi3O9:Ce3+,Li+,Tb3+ phosphor with energy transfer for near-UV white LEDs
摘要： Phosphor-converted white light emitting diodes (w-LEDs), with high luminous ef?ciency, low energy consumption, extended lifetime, and eco-friendly nature, have revolutionized various industries. Among them, an alkaline earth silicate-based phosphor host, Na4CaSi3O9, shows good crystal structure stability and ?exible properties for diverse application. Here, Ce3t/Lit and Tb3t/Lit co-doped Na4CaSi3O9 phosphors are fabricated by the standard solid-state reaction approach. The Ce3t/Lit-activated phosphors show strong absorption within 200e400 nm and exhibit a blue emission centered at 423 nm. The quenching concentration of Ce3t appears at x ? 0.05 and can be attributed to the dipoleequadrupole interaction. When Tb3t ions are co-doped, the Na4CaSi3O9:Ce3t/Lit phosphor emission can be adjusted from blue to green under the irradiation of 365 nm through the dipoleedipole interaction induced energy transfer from Ce3t to Tb3t ions with a maximum value of 28.32%. This study highlights the Na4CaSi3O9:Ce3t/Lit,Tb3t/Lit phosphors as a new and ef?cient material for w-LED applications.
关键词： Phosphor,Solid-state reaction,Luminescence,LED,Energy transfer
更新于2025-09-23 15:21:01
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Excellent human eye sensitivity matching, high luminous efficacy, high quantum yield and thermal stability of narrow-band red-emitting SrLiAl3N4:Eu2+ phosphor
摘要： Here, using the safety raw materials Li3N, Sr3N2 and Eu2O3 instead of LiAlH4, SrH2 and EuF3 (besides AlN), the nitride phosphor SrLiAl3N4:Eu2+ (SLA:Eu2+) was synthesized in the glove box (O2＜0.1ppm, H2O＜0.1ppm) under continuous purified nitrogen flow. It avoids the dangerous synthesis and production environment negative factors caused by the dangerous materials of LiAlH4 and SrH2. The luminescence properties of SLA:Eu2+ with different aid-sintering additives (LiCl and SrF2) were improved, such as red emission (~ 653 nm), narrow full-width at half-maximum (FWHM ~ 50nm), highly luminous efficacy (23.6 lm/W) and superior thermal property. The narrow band emission of SLA:Eu2+ fits well with the curve of human eye sensitivity and leads to excellent chromatic saturation. Moreover, the white light-emitting-diodes (LEDs) devices have been fabricated by combining a 450 nm blue chip with the commercial LCN630, LCL530 phosphor and as-prepared red-emitting phosphor SLA:0.004Eu2+, 0.1LiCl, 0.3SrF2 which shows a greater color rendering index (Ra) value of 90.3 and low correlated color temperature (CCT) of 2726K. Importantly, the luminous efficacy, the purity and R9 value increased up to 110.10lm/W, 62.2% and 55, respectively. The results exhibit the materials with high luminous efficacy, low correlated color temperature and narrow band red emission, delivering the foundation for white LEDs.
关键词： Phosphor,Luminescence
更新于2025-09-23 15:21:01
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Tunable luminescence of (Sr <sub/>1?x</sub> Ca <sub/>x</sub> ) <sub/>1.97</sub> MgSi <sub/>2</sub> O <sub/>7</sub> :0.03Eu <sup>2+</sup> solid solution phosphors for cirtopic LEDs
摘要： In order to realize the 490 nm single-peak emission for cirtopic light-emitting diodes (LEDs), a series of iso-structural (Sr1?xCax)1.97MgSi2O7:0.03Eu2+ (x = 0, 0.2, 0.3, 0.4, 0.8, 1) phosphors with melilite structure have been prepared by traditional solid-state reaction. The x-ray Diffraction (XRD) patterns and regular lattice parameters confirm the formation of (Sr1?xCax)2MgSi2O7 solid solution. Broad band excitation spectra were observed in the ultraviolet region of these phosphors. The photoluminescence spectra of (Sr1?xCax)1.97MgSi2O7:0.03Eu2+ solid solution phosphors give continuously tunable emission from 466 [Sr2MgSi2O7:Eu2+, (x = 0)] to 527 nm [Ca2MgSi2O7:Eu2+, (x = 1)]. Phosphors with an illuminating centre at 486 and 490 nm were obtained when adjusting the x value to 0.3 and 0.4 respectively. By measuring the quantum efficiency (QE) and contrasting with the spectral sensitivity function of cirtopic, (Sr1?xCax)1.97MgSi2O7:0.03Eu2+ (x = 0.3, 0.4) phosphors have potential value in cirtopic vision.
关键词： solid solution phosphor,melilite structure,cirtopic LED
更新于2025-09-23 15:19:57
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Single-phased chromaticity-tunable phosphor of Sr <sub/>4</sub> Al <sub/>14</sub> O <sub/>25</sub> : Eu <sup>2+/3+</sup> co-doped with Tb <sup>3+</sup> for white-light-emitting diodes
摘要： The single-phased phosphors doped with Eu2+ and Eu3+ have shown the potential for the application of white-light-emitting diodes (wLEDs). In this manuscript, we introduced a simple method of co-doping terbium ions into the Sr4Al14O25: Eu2+/3+ phosphor to achieve the tunable chromaticity and the good color rendering performance. The phosphor was synthesized through the conventional solid-state reaction in a non-reducing atmosphere. The phase purity was examined by XRD analysis, and the luminescent properties were discussed systematically depending on the room- and low-temperature photoluminescence spectra. The emission spectrum of the sample Sr4Al14O25: 0.01Eu2+/3+, 0.06Tb3+ covered the whole visible spectral region with a white light emission (0.2799, 0.3059), indicating that the present phosphor could be suitable for the wLEDs application.
关键词： self-reduction,wLEDs,phosphor,photoluminescence
更新于2025-09-23 15:19:57
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Developing Lattice Matched ZnMgSe Shells on InZnP Quantum Dots for Phosphor Applications
摘要： Indium phosphide quantum dots (QDs) have drawn attention as alternatives to cadmium and lead based QDs that are currently used as phosphors in lamps and displays. The main drawbacks of InP QDs are, in general, a lower photoluminescence quantum yield (PLQY), a decreased color purity and poor chemical stability. In this research, we attempted to increase the PLQY and stability of indium phosphide QDs by developing lattice matched InP/MgSe core-shell nano-heterostructures. The choice of MgSe comes from the fact that, in theory, it has a near-perfect lattice match with InP, provided MgSe is grown in the zinc blende crystal structure, which can be achieved by alloying with zinc. To retain lattice matching we used Zn in both the core and the shell and we fabricated InZnP/ZnxMg1-xSe core/shell QDs. To identify the most suitable conditions for shell growth, we first developed a synthesis route to ZnxMg1-xSe nanocrystals (NCs) wherein Mg is effectively incorporated. Our optimized procedure was employed for the successful growth of ZnxMg1-xSe shells around In(Zn)P QDs. The corresponding core/shell systems exhibit PLQYs higher than those of the starting In(Zn)P QDs and, more importantly, a higher color purity upon increasing the Mg content. The results are discussed in the context of a reduced density of interface states upon using better lattice matched ZnxMg1-xSe shells.
关键词： MgSe,Quantum Dots,lattice matching,core-shell,InP,phosphor
更新于2025-09-23 15:19:57
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Study of energy transfer from Bi3+ to Tb3+ in Y2O3 phosphor and its application for W-LED
摘要： Y2O3 activated with different activators were prepared by co-precipitation method. The prepared phosphors were characterized by XRD, SEM and photoluminescence (PL) techniques. The Tb3+ doped Y2O3 phosphor shows characteristic green emission due to 5D4 to 7Fj transitions of Tb3+ ion. The Bi3+ doped Y2O3 phosphor shows PL emission in blue region due to the transition between excited 3P1 state and ground state 1S0 of Bi3+ ion. The multiple systems of Tb3+emission lines in Y2O3:Tb3+ and two types of excitation and emission spectra of Y2O3:Bi3+ phosphors are due to two Y3+ sites in the host structure with C2 and S6 symmetries. Due to the addition of transition metal ion Bi3+ in Y2O3:Tb3+ lattice, the excitation efficiency is enhanced throughout the spectral range from 300 nm to 400 nm. Bi3+ ions absorb N-UV radiation and, subsequently, the energy is transferred from the sensitizer Bi3+ to activator Tb3+ and emitted via 5D4 to 7Fj transitions of Tb3+ ion. From the spectral properties of Y2O3:Bi3+ and Y2O3:Tb3+, Bi3+, it is established that the prepared phosphors are useful in near UV excited LED (solid state lighting) application.
关键词： Phosphor,Y2O3,W-LED,Energy transfer
更新于2025-09-23 15:19:57
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High performance red/deep-red emitting phosphors for white LEDs
摘要： Highly efficient oxide based red line emitters are still bottleneck for the smart white LEDs. In the present investigation, sequences of narrow band red emitting phosphors were synthesized through the conventional solid-state technique. The X-ray diffraction studies reveals that the synthesized phosphors were crystallized in the trigonal phase with space group I41/a (88). Under 395 nm excitation, NaSrGd(MoO4)3:Eu3+ phosphors shown sharp red emission around at 616 nm because of the 5D0→7F2 transition (ED transition). Moreover, the internal quantum efficiency (IQE) was found to be 82 %, and the thermal stability study showed that the NaSrGd0.5Eu0.5(MoO4)3 phosphor retains the emission intensity around 71.5% at 423K of its initial room temperature. The red LEDs were designed for the NaSrGd0.5Eu0.5(MoO4)3 red phosphors with the NUV LED chip. White LED also been fabricated by conjugating the blue LED with yellow dye + red phosphor and the LED shown CCT (6823 K), CRI (74%), CIE (0.306, 0.331). The Sm3+ and Eu3+ co-doped deep red phosphor were synthesized and studied for the plant growth. The LED emission of Sm3+ and Eu3+ co-doped phosphor is completely covers the absorption spectrum of Phytochrome Pr. All of these consequences revealed that the synthesized phosphor could be the efficient red emitting phosphor for warm white LEDs and plant growth filed research.
关键词： Eu3+ red phosphor,Quantum Yield,White LED,Plant growth,Molybdate
更新于2025-09-23 15:19:57